[PATCH 1/2] ath9k: recover the chip from tx/rx stuck

* [PATCH 1/2] ath9k: recover the chip from tx/rx stuck
@ 2012-02-01 16:05 Rajkumar Manoharan
  2012-02-01 16:05 ` [PATCH 2/2] ath9k_hw: improve ANI processing and rx desensitizing parameters Rajkumar Manoharan
                   ` (4 more replies)
  0 siblings, 5 replies; 20+ messages in thread
From: Rajkumar Manoharan @ 2012-02-01 16:05 UTC (permalink / raw)
  To: linville; +Cc: linux-wireless, Rajkumar Manoharan, Paul Stewart

In the following scenario, where the distance b/w STA and AP is ~10m
or in a shield environment by placing an attenuator with reduced AP
txpower, the station started reporting with beacon loss and got
disconnected whenever the chariot endpoint was initiated with BiDi
traffic. In such state, two different stuck cases were observed.

  * rx clear is stuck at low for more than 100ms
  * dcu chain and complete state is stuck.

This patch detects the stuck state if the beacons are not received for
more than 300ms. In the above matching conditions, trigger a chip
reset to recover. This issue was originally reported in 3.0 kernel with
AR9382 chip by having two stations associated with two different APs in
the same channel and was attenuated/controlled by Azimuth ADEPT-n box.

Cc: Paul Stewart <pstew@google.com>
Reported-by: Gary Morain <gmorain@google.com>
Signed-off-by: Rajkumar Manoharan <rmanohar@qca.qualcomm.com>
---
 drivers/net/wireless/ath/ath.h         |    1 +
 drivers/net/wireless/ath/ath9k/ath9k.h |    4 +
 drivers/net/wireless/ath/ath9k/init.c  |    1 +
 drivers/net/wireless/ath/ath9k/main.c  |  142 ++++++++++++++++++++++++++++++++
 drivers/net/wireless/ath/ath9k/recv.c  |    4 +
 drivers/net/wireless/ath/hw.c          |    5 +
 6 files changed, 157 insertions(+), 0 deletions(-)

diff --git a/drivers/net/wireless/ath/ath.h b/drivers/net/wireless/ath/ath.h
index efc0111..f11f397 100644
--- a/drivers/net/wireless/ath/ath.h
+++ b/drivers/net/wireless/ath/ath.h
@@ -150,6 +150,7 @@ struct ath_common {
 	spinlock_t cc_lock;
 	struct ath_cycle_counters cc_ani;
 	struct ath_cycle_counters cc_survey;
+	struct ath_cycle_counters cc_rxpoll;
 
 	struct ath_regulatory regulatory;
 	struct ath_regulatory reg_world_copy;
diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h b/drivers/net/wireless/ath/ath9k/ath9k.h
index 171ccf7..748a277 100644
--- a/drivers/net/wireless/ath/ath9k/ath9k.h
+++ b/drivers/net/wireless/ath/ath9k/ath9k.h
@@ -306,6 +306,7 @@ struct ath_rx_edma {
 struct ath_rx {
 	u8 defant;
 	u8 rxotherant;
+	bool stop_rx_poll;
 	u32 *rxlink;
 	unsigned int rxfilter;
 	spinlock_t rxbuflock;
@@ -431,6 +432,8 @@ void ath9k_set_beaconing_status(struct ath_softc *sc, bool status);
 void ath_reset_work(struct work_struct *work);
 void ath_hw_check(struct work_struct *work);
 void ath_hw_pll_work(struct work_struct *work);
+void ath_rx_poll_work(unsigned long data);
+void ath_start_rx_poll(struct ath_softc *sc, const u32 msec);
 void ath_paprd_calibrate(struct work_struct *work);
 void ath_ani_calibrate(unsigned long data);
 void ath_start_ani(struct ath_common *common);
@@ -650,6 +653,7 @@ struct ath_softc {
 	struct ath_beacon_config cur_beacon_conf;
 	struct delayed_work tx_complete_work;
 	struct delayed_work hw_pll_work;
+	struct timer_list rx_poll_timer;
 	struct ath_btcoex btcoex;
 	struct ath_mci_coex mci_coex;
 
diff --git a/drivers/net/wireless/ath/ath9k/init.c b/drivers/net/wireless/ath/ath9k/init.c
index abf9435..df49b38 100644
--- a/drivers/net/wireless/ath/ath9k/init.c
+++ b/drivers/net/wireless/ath/ath9k/init.c
@@ -844,6 +844,7 @@ int ath9k_init_device(u16 devid, struct ath_softc *sc,
 	INIT_WORK(&sc->hw_check_work, ath_hw_check);
 	INIT_WORK(&sc->paprd_work, ath_paprd_calibrate);
 	INIT_DELAYED_WORK(&sc->hw_pll_work, ath_hw_pll_work);
+	setup_timer(&sc->rx_poll_timer, ath_rx_poll_work, (unsigned long)sc);
 	sc->last_rssi = ATH_RSSI_DUMMY_MARKER;
 
 	ath_init_leds(sc);
diff --git a/drivers/net/wireless/ath/ath9k/main.c b/drivers/net/wireless/ath/ath9k/main.c
index ec82e92..b4322cb 100644
--- a/drivers/net/wireless/ath/ath9k/main.c
+++ b/drivers/net/wireless/ath/ath9k/main.c
@@ -241,6 +241,7 @@ static bool ath_prepare_reset(struct ath_softc *sc, bool retry_tx, bool flush)
 
 	sc->hw_busy_count = 0;
 	del_timer_sync(&common->ani.timer);
+	del_timer_sync(&sc->rx_poll_timer);
 
 	ath9k_debug_samp_bb_mac(sc);
 	ath9k_hw_disable_interrupts(ah);
@@ -282,6 +283,7 @@ static bool ath_complete_reset(struct ath_softc *sc, bool start)
 
 		ieee80211_queue_delayed_work(sc->hw, &sc->tx_complete_work, 0);
 		ieee80211_queue_delayed_work(sc->hw, &sc->hw_pll_work, HZ/2);
+		ath_start_rx_poll(sc, 100);
 		if (!common->disable_ani)
 			ath_start_ani(common);
 	}
@@ -1179,6 +1181,7 @@ static void ath9k_stop(struct ieee80211_hw *hw)
 	mutex_lock(&sc->mutex);
 
 	ath_cancel_work(sc);
+	del_timer_sync(&sc->rx_poll_timer);
 
 	if (sc->sc_flags & SC_OP_INVALID) {
 		ath_dbg(common, ANY, "Device not present\n");
@@ -1418,6 +1421,141 @@ static void ath9k_do_vif_add_setup(struct ieee80211_hw *hw,
 	}
 }
 
+static bool ath9k_check_dcu_chain_state(u32 dma_dbg, int max_limit,
+					int *hang_state, int *hang_pos)
+{
+	static u32 hang_sign[] = {5, 6, 9};
+	u32 chain_state, dcs_pos, i;
+
+	for (dcs_pos = 0; dcs_pos < max_limit; dcs_pos++) {
+		chain_state = (dma_dbg >> (5 * dcs_pos)) & 0x1f;
+		for (i = 0; i < 3; i++) {
+			if (chain_state == hang_sign[i]) {
+				*hang_state = chain_state;
+				*hang_pos = dcs_pos;
+				return true;
+			}
+		}
+	}
+	return false;
+}
+
+#define DCU_COMPLETE_STATE  1
+#define NUM_STATUS_READS    50
+static bool ath9k_detect_mac_hang(struct ath_hw *ah)
+{
+	u32 chain_state, comp_state, dcs_reg = AR_DMADBG_4;
+	u32 i, hang_pos, hang_state;
+
+	comp_state = REG_READ(ah, AR_DMADBG_6);
+
+	if ((comp_state & 0x3) != DCU_COMPLETE_STATE) {
+		ath_dbg(ath9k_hw_common(ah), RESET,
+			"MAC Hang signature not found at DCU complete\n");
+		return false;
+	}
+
+	chain_state = REG_READ(ah, dcs_reg);
+	if (ath9k_check_dcu_chain_state(chain_state, 6, &hang_state, &hang_pos))
+		goto hang_check_iter;
+
+	dcs_reg = AR_DMADBG_5;
+	chain_state = REG_READ(ah, dcs_reg);
+	if (ath9k_check_dcu_chain_state(chain_state, 4, &hang_state, &hang_pos))
+		goto hang_check_iter;
+
+	ath_dbg(ath9k_hw_common(ah), RESET,
+		"MAC Hang signature 1 not found\n");
+	return false;
+
+hang_check_iter:
+	ath_dbg(ath9k_hw_common(ah), RESET,
+		"DCU registers: chain %08x complete %08x Hang: state %d pos %d\n",
+		chain_state, comp_state, hang_state, hang_pos);
+
+	for (i = 0; i < NUM_STATUS_READS; i++) {
+		chain_state = REG_READ(ah, dcs_reg);
+		chain_state = (chain_state >> (5 * hang_pos)) & 0x1f;
+		comp_state = REG_READ(ah, AR_DMADBG_6);
+
+		if (((comp_state & 0x3) != DCU_COMPLETE_STATE) ||
+		    (chain_state != hang_state))
+			return false;
+	}
+
+	ath_dbg(ath9k_hw_common(ah), RESET, "MAC Hang signature 1 found\n");
+
+	return true;
+}
+
+void ath_start_rx_poll(struct ath_softc *sc, const u32 msec)
+{
+	if (!AR_SREV_9300_20_OR_LATER(sc->sc_ah))
+		return;
+
+	if (!(sc->sc_flags & SC_OP_PRIM_STA_VIF))
+		return;
+
+	mod_timer(&sc->rx_poll_timer, jiffies + msecs_to_jiffies(msec));
+}
+
+void ath_rx_poll_work(unsigned long data)
+{
+	struct ath_softc *sc = (struct ath_softc *)data;
+	struct ath_hw *ah = sc->sc_ah;
+	struct ath_common *common = ath9k_hw_common(ah);
+	static u32 iteration, match_count;
+	static u64 last_run;
+	unsigned long flags;
+	u32 rx_clear, rx, tx, delay = 10;
+
+	spin_lock_bh(&sc->rx.rxbuflock);
+	if (jiffies_to_msecs(jiffies - last_run) > 30)
+		iteration = match_count = 0;
+	else {
+		if (sc->rx.stop_rx_poll && iteration) {
+			spin_unlock_bh(&sc->rx.rxbuflock);
+			iteration = match_count = 0;
+			return;
+		}
+		iteration += 1;
+	}
+	sc->rx.stop_rx_poll = false;
+	spin_unlock_bh(&sc->rx.rxbuflock);
+	sc->ps_flags |= PS_WAIT_FOR_BEACON;
+	ath9k_ps_wakeup(sc);
+
+	spin_lock_irqsave(&common->cc_lock, flags);
+	ath_hw_cycle_counters_update(common);
+
+	rx_clear = common->cc_rxpoll.rx_busy * 100 / common->cc_rxpoll.cycles;
+	rx = common->cc_rxpoll.rx_frame * 100 / common->cc_rxpoll.cycles;
+	tx = common->cc_rxpoll.tx_frame * 100 / common->cc_rxpoll.cycles;
+	memset(&common->cc_rxpoll, 0, sizeof(common->cc_rxpoll));
+	spin_unlock_irqrestore(&common->cc_lock, flags);
+
+	last_run = jiffies;
+	if (rx_clear > 98) {
+		ath_dbg(common, RESET,
+			"rx clear %d match count %d iteration %d\n",
+		       rx_clear, match_count, iteration);
+		if (match_count++ > 9)
+			goto queue_reset_work;
+	} else if (ath9k_detect_mac_hang(ah))
+		goto queue_reset_work;
+	else if (iteration >= 15) {
+		iteration = match_count = 0;
+		delay = 200;
+	}
+	ath9k_ps_restore(sc);
+	ath_start_rx_poll(sc, delay);
+	return;
+
+queue_reset_work:
+	ath9k_ps_restore(sc);
+	ieee80211_queue_work(sc->hw, &sc->hw_reset_work);
+	iteration = match_count = 0;
+}
 
 static int ath9k_add_interface(struct ieee80211_hw *hw,
 			       struct ieee80211_vif *vif)
@@ -1948,6 +2086,8 @@ static void ath9k_bss_iter(void *data, u8 *mac, struct ieee80211_vif *vif)
 		if (!common->disable_ani) {
 			sc->sc_flags |= SC_OP_ANI_RUN;
 			ath_start_ani(common);
+			sc->rx.stop_rx_poll = false;
+			ath_start_rx_poll(sc, 300);
 		}
 
 	}
@@ -1984,6 +2124,7 @@ static void ath9k_config_bss(struct ath_softc *sc, struct ieee80211_vif *vif)
 		/* Stop ANI */
 		sc->sc_flags &= ~SC_OP_ANI_RUN;
 		del_timer_sync(&common->ani.timer);
+		del_timer_sync(&sc->rx_poll_timer);
 		memset(&sc->caldata, 0, sizeof(sc->caldata));
 	}
 }
@@ -2027,6 +2168,7 @@ static void ath9k_bss_info_changed(struct ieee80211_hw *hw,
 		} else {
 			sc->sc_flags &= ~SC_OP_ANI_RUN;
 			del_timer_sync(&common->ani.timer);
+			del_timer_sync(&sc->rx_poll_timer);
 		}
 	}
 
diff --git a/drivers/net/wireless/ath/ath9k/recv.c b/drivers/net/wireless/ath/ath9k/recv.c
index 0e666fb..989b1ee 100644
--- a/drivers/net/wireless/ath/ath9k/recv.c
+++ b/drivers/net/wireless/ath/ath9k/recv.c
@@ -1837,6 +1837,10 @@ int ath_rx_tasklet(struct ath_softc *sc, int flush, bool hp)
 		if (sc->sc_flags & SC_OP_RXFLUSH)
 			goto requeue_drop_frag;
 
+		if (rs.is_mybeacon) {
+			sc->rx.stop_rx_poll = true;
+			ath_start_rx_poll(sc, 300);
+		}
 		rxs->mactime = (tsf & ~0xffffffffULL) | rs.rs_tstamp;
 		if (rs.rs_tstamp > tsf_lower &&
 		    unlikely(rs.rs_tstamp - tsf_lower > 0x10000000))
diff --git a/drivers/net/wireless/ath/hw.c b/drivers/net/wireless/ath/hw.c
index 19befb3..f1821ea 100644
--- a/drivers/net/wireless/ath/hw.c
+++ b/drivers/net/wireless/ath/hw.c
@@ -166,6 +166,11 @@ void ath_hw_cycle_counters_update(struct ath_common *common)
 	common->cc_survey.rx_busy += busy;
 	common->cc_survey.rx_frame += rx;
 	common->cc_survey.tx_frame += tx;
+
+	common->cc_rxpoll.cycles += cycles;
+	common->cc_rxpoll.rx_busy += busy;
+	common->cc_rxpoll.rx_frame += rx;
+	common->cc_rxpoll.tx_frame += tx;
 }
 EXPORT_SYMBOL(ath_hw_cycle_counters_update);
 
-- 
1.7.9


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